JP5886022B2 - Method for removing oxide film on copper or copper base alloy surface - Google Patents

Description

  The present invention relates to a method for removing an oxide film on the surface of copper or a copper base alloy, and in particular, after removing the oxide film by immersing the copper or copper base alloy having an oxide film formed on the surface in a pickling bath, Electrolyze the pickling solution containing the oxide film in the electrolytic cell to recover high-purity copper or copper-based alloy with good handling properties, and return the pickled solution after electrolysis to the pickling bath for reuse. The present invention relates to a method for removing an oxide film on the surface of copper or a copper-based alloy.

  For example, copper or copper-base alloy after heat treatment such as hot rolling or hot extrusion is pickled or etched for the purpose of removing oxide film or fine defects generated on the surface. Processing is normal. For the pickling or etching solution, sulfuric acid or sulfuric acid mixed with hydrogen peroxide in sulfuric acid, hydrochloric acid or nitric acid is used. In some cases, additives such as hydrofluoric acid and other surfactants are also shared. The In recent years, from the viewpoint of resource recovery and wastewater treatment, copper oxide or metal copper dissolved in the solution by pickling or etching is recovered by electrolysis, and the used pickling solution or etching solution is removed. Recycling has been widely attempted.

  In Patent Document 1, as a method for regenerating and recovering nitric acid and metallic copper powder by electrolysis from waste liquid containing copper and nitric acid produced in the copper pickling finishing process, it is produced in the pickling process of copper or copper alloy products. A waste solution containing copper and nitric acid, at least the anode of both electrodes is a ferrite electrode, and a combination of an anion membrane and a cation membrane between the anode and the cathode, or a combination of a plurality of amphoteric membranes, In the apparatus in which the intermediate region and the cathode region are formed, electrolytic treatment is performed while maintaining the pH of the cathode region within the range of 0.2 to 2.0, nitric acid is added to the anode region, and powdered copper is added to the cathode region. A method of regenerating is disclosed.

  In Patent Document 2, tin is efficiently removed without generating tin oxide and hydroxide that become a fine solid matter, which becomes a problem when the copper alloy pickling waste liquid is reused. As a method of efficiently recovering the copper in the interior and reusing the treated sulfuric acid, the waste liquid is heated to 40 ° C. or more, and pre-treatment for selectively precipitating and separating tin is performed, followed by regeneration treatment. A characteristic method for reclaiming a copper alloy pickling waste liquid is disclosed.

Japanese Patent Publication No. 61-60148 JP 2003-342863 A

  In the conventional method for removing an oxide film formed on the surface of copper or a copper base alloy, after removing the oxide film in a pickling bath, the pickling solution containing the oxide film is electrolyzed in an electrolytic bath, It is difficult to efficiently recover high-purity copper or copper-based alloy that can be used as a recyclable raw material with good handling properties, and it is also possible to return the pickling solution after electrolysis to the pickling bath for reuse. It was impossible.

  In the present invention, the above-mentioned problems are solved, and after removing the oxide film by immersing copper or copper-based alloy having an oxide film formed on the surface of the pickling bath, the pickling solution containing the oxide film is removed from the electrolytic bath. The high-purity copper or copper-based alloy that can be used as a recyclable raw material with good handleability is efficiently recovered, and the pickling solution after electrolysis is returned to the pickling bath for reuse. Provided is a method for removing an oxide film on the surface of copper or a copper-based alloy that can be performed.

As a result of intensive studies, the present inventors have determined that at least one oxidation selected from the group consisting of sulfuric acid: 50 to 400 g / L, nitric acid, hydrogen peroxide, peroxodisulfate ion, and trivalent iron ion as the pickling solution. Agent: 1 to 100 g / L, at least one additive selected from the group consisting of aromatic sulfonic acid, aromatic sulfonate, and alkylamine: 0.01 to 10 g / L, alkylbenzene sulfonic acid, alkylbenzene sulfonate At least one additive selected from the group consisting of: 0.005-10 g / L, and copper sulfate: 10-300 g / L, and using a pickling solution having a surface tension of less than 50 dyn / cm Thus, the oxide film can be removed efficiently, and the pickling solution containing the removed oxide film is electrolyzed in an electrolytic cell, so that the recyclability is improved. It has been found that high-purity copper or copper-based alloys that can be used as raw materials can be recovered.
Furthermore, the pickling solution can be reused efficiently by adding the oxidizing agent and additives corresponding to the amount consumed during removal of the oxide film and electrolysis to the pickling solution after electrolysis and returning it to the pickling bath. I found.

That is, the method for removing an oxide film on the surface of copper or copper base alloy according to the present invention is a method for removing an oxide film formed on the surface of copper or copper base alloy, comprising sulfuric acid: 50 to 400 g / L, nitric acid, excess At least one oxidizing agent selected from the group consisting of hydrogen oxide, peroxodisulfate ion, and trivalent iron ion: 1 to 100 g / L, selected from the group consisting of aromatic sulfonic acid, aromatic sulfonate, and alkylamine At least one additive: 0.01 to 10 g / L, at least one additive selected from the group consisting of alkylbenzene sulfonic acid and alkylbenzene sulfonate: 0.005 to 10 g / L, and copper sulfate: 10 Copper or copper-based alloy having an oxide film formed on the surface thereof in a pickling bath containing a pickling solution containing 300 g / L and having a surface tension of less than 50 dyn / cm And removing the oxide film, the pickling solution containing the removed oxide film is electrolyzed in an electrolytic bath to recover copper or a copper-based alloy in the oxide film, To the pickling solution after decomposition, the oxidizing agent and the additive corresponding to the amount consumed during the removal of the oxide film and the electrolysis are added, and then returned to the pickling bath and reused as the pickling solution. It is characterized by.

If the sulfuric acid is less than 50 g / L, the effect of removing the oxide film is reduced. If it exceeds 400 g / L, the effect is saturated and the cost is wasted.
If the oxidizing agent is less than 1 g / L, the effect of removing the oxide film is lowered, and if it exceeds 100 g / L, the amount of gas generated at the time of removal is disadvantageously increased. The generated gas depends mainly on the oxidant used, but is mainly NOx and oxygen gas.

At least one additive selected from the group consisting of aromatic sulfonic acids, aromatic sulfonates, and alkylamines may be used when the processing oil brought in from the previous step attached to the copper or copper-based alloy surface is pickled. Even if it is contaminated, high-purity copper or copper-based alloy that can be used as a recyclable raw material with good handling properties is deposited on the cathode during electrolysis, and hydrogen peroxide is prevented from being reduced and decomposed on the cathode. . Moreover, since it acts as a stabilizer for the oxidant in the pickling solution, it also serves to suppress the consumption of the oxidant.
Even if the addition amount is less than 0.01 g / L or exceeds 10 g / L, the above-mentioned effects cannot be obtained.

At least one additive selected from the group consisting of alkyl benzene sulfonic acid and alkyl benzene sulfonate is chemically stable even in pickling solution, and reduces the surface tension of pickling solution over a long period of time to prevent mist scattering. And increase the pickling ability of the pickling solution to increase the pickling ability. In particular, it is possible to prevent a large amount of sulfuric acid mist from being scattered due to oxygen gas generated from the cathode during electrolysis.
Even if the addition amount is less than 0.005 g / L or more than 10 g / L, the above-mentioned effect cannot be obtained.

  A combination of at least one additive selected from the group consisting of aromatic sulfones, aromatic sulfonates and alkylamines and at least one additive selected from the group consisting of alkylbenzene sulfonic acids and alkylbenzene sulfonates Thus, a good effect in the present invention can be obtained.

  If the copper sulfate is less than 10 g / L, the efficiency of electrolysis in the next step is reduced, and if it exceeds 300 g / L, the copper is precipitated in the removal solution and is wasted because it becomes close to the saturation solubility.

  By adding the oxidizing agent and additives corresponding to the amount consumed during the removal of the oxide film and electrolysis to the pickled solution after electrolysis, it can be efficiently reused as a pickling solution by returning it to the pickling bath. This enables not only batch processing but also continuous removal of the oxide film on the surface of copper or copper-based alloy. Although depending on the type of copper or copper-based alloy, the amount of oxidant and additive added (consumed) is about 0.5 to 10% of the initial amount.

The method for removing an oxide film on the surface of copper or copper-based alloy according to the present invention is characterized in that the pickling solution has a surface tension of less than 50 dyn / cm.
By making the surface tension of the pickling solution less than 50 dyn / cm with at least one additive selected from the group consisting mainly of alkylbenzene sulfonic acid and alkylbenzene sulfonate, oxygen gas from the cathode is reduced during electrolysis. It is possible to efficiently prevent a large amount of sulfuric acid mist from being scattered, and it is possible to more efficiently recover high-purity copper or a copper-based alloy that can be used as a recycled raw material with good handling properties.

Moreover, the copper or copper base alloy that can be used as the reclaimed raw material of the present invention is obtained by the above-described method for removing an oxide film on the surface of copper or copper base alloy.
The pickling solution contains a suitable and optimum amount of electrolyte component required for recovering copper oxide or a copper oxide base alloy contained in the oxide film, or metal copper or a metal copper base alloy by electrolysis. Since it is contained, it is possible to electrolyze the pickling solution including the removed oxide film without adding any special means, and to efficiently recover copper or a copper-based alloy that can be used as a recycled material. Can do.

  Also, the copper or copper-based alloy recovered on the cathode by electrolysis is not in the form of powder as recovered by the prior art, it is a plate having high purity and appropriate hardness, and has good handling properties. Ingots that are easy to wash and difficult to contain impurities, so that the recovered copper or copper-base alloy is melt-cast using recycled material as a raw material have a low content of impurities, and can be used for subsequent hot rolling and hot extrusion. Problems such as cracking are unlikely to occur.

  In the method for removing an oxide film on the surface of copper or a copper base alloy according to the present invention, after removing the oxide film by immersing the copper or copper base alloy having the oxide film formed on the surface in a pickling bath, the acid containing the oxide film is removed. By electrolyzing the washing solution in an electrolytic cell, it is possible to efficiently recover high-purity copper or copper-based alloy that can be used as a recyclable raw material with good handling properties. It can be returned to the pickling bath and reused.

It is the schematic of the apparatus of the one implementation corresponding example for implementing this invention.

  FIG. 1 is a schematic view of an apparatus corresponding to one embodiment for carrying out the present invention. In the oxide film removing apparatus 1 of the present invention, a pickling solution 2 for an oxide film on the surface of copper or a copper base alloy is filled. Then, copper or a copper-based alloy 4 is immersed in the pickling bath 3, and the oxide film on the surface is removed in the pickling solution 2. Although the oxide film has a thickness of 0.05 to 10 μm, depending on the degree of heat treatment or the like in the previous process, the temperature of the oxide film removal liquid 2 is suitably 30 to 60 ° C., and the immersion time is 30 to 120 minutes is preferable. The copper or copper-based alloy 4 from which the oxide film has been removed is transported from the pickling bath 3 and used for the next step.

  The pickling solution 2 is sulfuric acid: 50 to 400 g / L, at least one oxidizing agent selected from the group consisting of nitric acid, hydrogen peroxide, peroxodisulfate ion, and trivalent iron ion: 1 to 100 g / L, aromatic At least one additive selected from the group consisting of sulfonic acid, aromatic sulfonate and alkylamine: 0.01 to 10 g / L, at least one selected from the group consisting of alkylbenzene sulfonic acid and alkylbenzene sulfonate Additive: 0.005 to 10 g / L, copper sulfate: 10 to 300 g / L.

If the sulfuric acid is less than 50 g / L, the effect of removing the oxide film is reduced. If it exceeds 400 g / L, the effect is saturated and the cost is wasted.
If the oxidizing agent is less than 1 g / L, the effect of removing the oxide film is lowered, and if it exceeds 100 g / L, the amount of gas generated at the time of removal is disadvantageously increased. The generated gas depends mainly on the oxidant used, but is mainly NOx and oxygen gas. As the oxidizing agent, for example, hydrogen peroxide, peroxodisulfate ion, trivalent iron ion, or the like can be used.

At least one additive selected from the group consisting of aromatic sulfonic acids, aromatic sulfonates, and alkylamines is processed oil brought from the previous step adhering to the copper or copper base alloy surface 4 is pickled. 2 can be deposited on the cathode 7 at the time of electrolysis, and can be deposited as hydrogen peroxide on the cathode 7. Prevents reductive decomposition. Moreover, since it acts as a stabilizer for the oxidant in the pickling solution 2, it also serves to suppress the consumption of the oxidant.
Even if the addition amount is less than 0.01 g / L or exceeds 10 g / L, the above-mentioned effects cannot be obtained.
Examples of the additive include aromatic sulfonic acids such as benzenesulfonic acid, toluenesulfonic acid, xylenesulfonic acid, ethylbenzenesulfonic acid, cumenesulfonic acid, phenolsulfonic acid, cresolsulfonic acid, sulfosalicylic acid, and sulfanilic acid.
As the alkylamine, methylamine, ethylamine, propylamine, butylamine, pentylamine can be used.

At least one additive selected from the group consisting of alkyl benzene sulfonic acid and alkyl benzene sulfonate is chemically stable even in the pickling solution 2, and lowers the surface tension of the pickling solution 2 over a long period of time, thereby spreading mist. This also has the effect of increasing the penetration of the pickling solution 2 and increasing the pickling ability. In particular, oxygen gas is generated from the cathode 7 during electrolysis, and a large amount of sulfuric acid mist is scattered. However, by adding alkylbenzenesulfonic acid, the surface tension of the pickling solution can be lowered and the scattering of sulfuric acid mist can be prevented. it can.
Even if the addition amount is less than 0.005 g / L or more than 10 g / L, the above-mentioned effect cannot be obtained.
Examples of the additive include octylbenzenesulfonic acid, nonylbenzenesulfonic acid, decylbenzenesulfonic acid, undecylbenzenesulfonic acid, dodecylbenzenesulfonic acid, tridecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, and mixtures thereof. Can be used.

  A combination of at least one additive selected from the group consisting of aromatic sulfonic acid, aromatic sulfonate, and alkylamine, and at least one additive selected from the group consisting of alkylbenzene sulfonic acid, alkylbenzene sulfonate Thus, the good effect of the present invention can be obtained.

  If the copper sulfate is less than 10 g / L, the efficiency of electrolysis in the next step is reduced, and if it exceeds 300 g / L, the copper is precipitated in the removal solution and is wasted because it becomes close to the saturation solubility.

  The surface tension of the pickling solution 2 is preferably less than 50 dyn / cm. By making the surface tension of the pickling solution 2 less than 50 dyn / cm with at least one additive selected from the group consisting mainly of alkylbenzene sulfonic acid and alkylbenzene sulfonate, oxygen gas from the cathode 7 during electrolysis As a result, it is possible to efficiently prevent a large amount of sulfuric acid mist from being scattered, and to efficiently recover high-purity copper or copper-based alloy 8 that can be used as a recycled raw material with good handling properties.

  Next, the pickling solution X containing the removed oxide film in the oxide film removal apparatus 1 is conveyed to the electrolytic treatment apparatus 5 by the pump P1. Copper or copper that can be efficiently used as a reclaimed raw material is electrolyzed by setting the anode 6 and the cathode 7 in the electrolytic treatment apparatus 5 and energizing between them, so that the pickling solution X including the removed oxide film is electrolyzed. The base alloy 8 is collected on the cathode 7.

The cathode 7 generally uses a tough pitch copper plate, but it is preferable to use an optimum material in accordance with the recovered copper or copper base alloy. It is preferable to use an iridium oxide-coated titanium plate for the anode 6, and depending on the degree of the oxide film, the oxide film can be electrolyzed at a current density of 3 to 10 A / dm ^{2 for} about 6 to 10 hours. Or copper-based alloy 8 is deposited on the cathode 7 in a plate shape that is easy to handle.

  The pickling solution 2 contains a suitable and optimal amount of electrolytic solution component required for electrolytic recovery of copper oxide or a copper oxide base alloy, or metal copper or a metal copper base alloy contained in the oxide film. Therefore, the pickling solution A including the removed oxide film can be electrolyzed without adding any special means, and thereby the copper or copper-based alloy 8 that can be efficiently used as a recycle raw material can be obtained. It can be recovered.

  Copper or copper-based alloy 8 recovered on the cathode by electrolysis is not in the form of powder as recovered in the prior art, it is a plate having high purity and appropriate hardness, and has good handling properties. Since it is easy to clean and difficult to contain impurities, the ingot in which the recovered copper or copper-based alloy 8 is melt-cast using the recycled raw material has a low content of impurities and is used for subsequent hot rolling and hot extrusion. Therefore, there is an advantage that cracking hardly occurs.

Next, the pickling solution Y after electrolysis in the electrolytic treatment apparatus 5 detects the amount of oxidant and additive consumed during the removal of the oxide film and electrolysis by an analytical instrument, and the corresponding oxidant and addition are detected. After adding the agent C, it is transported to the oxide film removing apparatus 1 by the pump P2 and recycled as a pickling solution. The amount of the oxidant and additive Z to be added is about 0.5 to 10% of the amount before consumption, although it depends on the amount of oxide film deposited and the type of copper or copper-based alloy.
The above treatment is a batch treatment, but it may be a continuous treatment. Depending on the type of copper or copper base alloy and the degree of its oxide film, the optimum immersion time is selected and the pickling solution 2 is circulated. It is also possible to continuously remove the oxide film on the surface.

Hot rolling (600 ° C., reduction ratio 50%) on a tough pitch copper (Cu: 99.92%, O: 300 ppm, P: 0 ppm) plate made by Mitsubishi Materials Corporation having a length of 500 mm, a width of 100 mm, and a thickness of 30 mm ) And quenched to prepare a tough pitch copper plate having a thickness of 15 mm. An oxide film having a thickness of about 0.7 μm was formed on the surface of the tough pitch copper plate.
The tough pitch copper plate was immersed in a pickling bath containing 1 m ³ of pickling solution having the composition and surface tension shown in Table 1 for 30 minutes at 40 ° C., then washed to remove the oxide film, and the tough pitch copper plate after removal of the oxide film The surface of was observed visually.

  In Table 1, A is nitric acid, B is hydrogen peroxide, C is peroxodisulfate ion, D is trivalent iron ion, E is benzenesulfonic acid, F is sodium benzenesulfonate, G is polyoxyethyleneamine, H is dodecyl Benzenesulfonic acid, I represents sodium dodecylbenzenesulfonate. In Table 1, those added two or more kinds are listed side by side, and the respective concentrations are described in the order of the order.

The results are shown in Table 1. The case where the oxide film on the surface of the tough pitch copper plate was completely removed and no trace of gas adhesion was observed was marked with ◯, and the oxide film was not completely removed and the gas adhesion trace was observed with x.
As a reference, when a normal mixed acid (sulfuric acid + nitric acid) was used as the pickling solution, removal of the oxide film was not completed unless soaked at 40 ° C. for 70 minutes, and a considerable trace of gas adhesion was observed.

Next, the entire amount of the pickling solution having the composition shown in Table 1 including the removed oxide film was transferred to an electrolytic cell, using a tough pitch copper plate as the cathode and an iridium oxide-coated titanium plate as the anode, a temperature of 40 ° C., and a current density of 5 A / dm. ^2. Electrolysis was performed at a distance of 50 mm between electrodes and a flow rate of 0.5 m / min for 8 hours to deposit copper from the oxide film in a plate shape on the cathode. The plate-like copper was recovered from the electrolytic cell, and average surface roughness Ra, copper purity, and surface hardness were measured.

(A) The surface roughness Ra of the copper plate surface was measured using SPM (SII Nanotechnology).
(B) The hardness of the copper plate surface was measured using MVK-G1 (AKASHI) at N = 3 according to the Vickers hardness test method, JIS Z 2244.
(C) The purity of the copper plate was determined by measuring impurities contained in copper and subtracting the impurity ratio from 100%.
(D) Impurity measurement is performed using a glow discharge mass spectrometer (GD-MS) except for C, and C is CO ₂ generated by high-frequency heating combustion in an oxygen atmosphere of a degreased copper sample. The infrared absorption of the gas was measured and converted to C amount.
The results are shown in Table 2.
From these results, it can be seen that the plate-like copper of the example has high purity, moderate hardness, good handleability, and is hardly affected by S in the cleaning liquid in the next cleaning step.

Next, these plate-like coppers were washed with a sulfuric acid aqueous solution and then melt-cast to produce an ingot, and the sulfur content (S content) in the ingot was measured. S content was measured by the infrared absorption method. Further, the ingot was heated to 600 ° C., a bar was formed by extrusion, and the presence or absence of cracks was visually observed. The results are shown in Table 2.
From these results, it is understood that the ingot melt-cast from the plate-like copper of the example has a small S content in the ingot, and the bar material extruded from the ingot does not have cracks.

  Next, the pickling solution after electrolysis is analyzed, and an oxidizing agent and an additive (0.002 g) corresponding to the amount consumed in the pickling solution are added, and the entire amount is returned to the pickling bath, and the next acid pickling solution is added. Using it as a washing solution, the removal of other tough pitch copper oxide films was carried out in the same manner as in Examples 1-8. This is repeated two more times, and the results of the fourth test for removing the oxide film are shown in Table 3. From this, it can be seen that the result of the fourth test is the same as the first test.

From these results, the recovered copper or copper alloy obtained by the method for removing an oxide film on the surface of the copper or copper-based alloy of the present invention is a high-purity copper or copper-based alloy that can be used as a recyclable raw material with good handling properties. It can be seen that the pickling solution according to the present invention can be sufficiently reused in the pickling bath by adding an oxidizing agent and an additive corresponding to the consumed amount. .
In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Oxide film removal apparatus 2 Pickling liquid 3 Pickling bath 4 Copper or copper base alloy 5 Electrolytic processing apparatus 6 Anode,
7 Cathode 8 Copper or copper-based alloy recovered on the cathode P1 Pump P2 Pump X Pickling solution containing oxide film Y Pickling solution after electrolysis Z Oxidizing agent and additive

Claims (2)

A method for removing an oxide film formed on a surface of copper or a copper-based alloy, which is selected from the group consisting of sulfuric acid: 50 to 400 g / L, nitric acid, hydrogen peroxide, peroxodisulfate ions, and trivalent iron ions. At least one oxidizing agent: 1 to 100 g / L, at least one additive selected from the group consisting of aromatic sulfonic acid, aromatic sulfonate, alkylamine: 0.01 to 10 g / L, alkylbenzenesulfonic acid, Contains a pickling solution containing at least one additive selected from the group consisting of alkylbenzene sulfonates: 0.005 to 10 g / L, and copper sulfate: 10 to 300 g / L, and has a surface tension of 50 dyn / cm After removing the oxide film by immersing copper or a copper-based alloy having an oxide film formed on the surface thereof in the pickling bath, the removed oxide film The pickling solution containing is electrolyzed in an electrolytic cell to recover the copper or copper-based alloy in the oxide film, and is further consumed in the pickling solution after electrolysis during the removal of the oxide film and the electrolysis. A method for removing an oxide film on the surface of copper or a copper-based alloy, comprising adding the oxidizing agent and the additive corresponding to a predetermined amount and then returning to the pickling bath and reusing it as the pickling solution. 2. The copper or copper base alloy surface according to claim 1, wherein the pickling solution containing the removed oxide film is electrolyzed in an electrolytic cell to deposit and recover plate-like copper or copper base alloy on the cathode. Of removing the oxide film.

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